Earthquakes how do they occur?

Question

How can i educate the public about why eathquakes occur? for my speech in my class?

Answer 1

Earthquakes (mostly) occur when a portion of the rigid crust fractures and moves due to movements in the underlying mantle. Specifically, stresses within the crust exceed the strength of the crust, and a strain or failure is expressed. We see this expression on the surface as scarfs or gashes. There are some deep mantle earthquakes that are not explained as above. One idea is that subducting oceanic crust undergoes as phase change to a denser solid. This phase change results in less space occupied and a collapse of the Mantle. Since the mantle underlies the crust, any reduction of space there removes support in that portion of the crust.

Answer 2

Which means you do not know the answer, is that what you want to say?
OR do you mean to say that you do not know how to prepare yourself to arrange the information for a class lecture?

If first, then search google, read wikipedia and there are numerous sources in the internet from governmental to private on quakes and quake science.

If second, you just need to do a little homework. You can start from a History of Quakes, List of big quakes and deaths/damages, Miracles happened such as people who miraculously managed to live and so on, Science behind the quakes, Advantages and Disadvantages after massive quakes such as loss of dinosaurs and birth of mankind, burying of huge forests and an eventual conversions to deeper oil fields, Loss and destruction of civilizations such as Harrappa-Mohenjodaro, Modern technologies and innovations in quake predictions and tsunami predictions, Tips to avoid disasters, such as modern building construction techniques, how to escape quakes and so on.

Answer 3

Take the picture from my web site for earth interior. The tectonic plates in lithosphere are moving at the rate of about 50 to 100 mm per year due to convection of heat . This creates pressure at tectonic plate boundary. The stress getting accumulated at that boundary.When the stress increases more than the bearable it slips and causes earthquakes. I have best demonstration C.D with me.As per the advice of the governor of our state I have prepared it to demonstrate to the scientist to prove how it was possible for me to issue the warning 2 hours before Tsunami struck our Tamilnadu coast. It was appreciated by them.But nobody came forward to approve my instruments that has helped me to issue the warning.
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